Preparation

Lightly butter a 3-quart baking dish. Working
in batches, blanch kale in a pot of boiling
lightly salted water until just softened, about
3 minutes. Using a slotted spoon, transfer
kale to a large bowl of ice water; let cool,
then drain. Squeeze out as much excess
water as possible by hand and transfer kale
to a work surface.

Repeat with mustard greens, blanching
for 2 minutes per batch. Coarsely chop all
greens and combine in a large bowl (you
should have 6 cups tightly packed greens).
Separate clumps and loosen chopped
leaves by hand.

Heat oil in a 12" skillet over medium
heat. Add breadcrumbs and cook,
stirring frequently, until golden and crispy,
8-10 minutes. Transfer to a large bowl;
stir in Parmesan and 1 teaspoon thyme leaves.
DO AHEAD: Greens and breadcrumbs can
be made 2 days ahead. Cover greens and
chill. Store breadcrumbs airtight at room
temperature.

Melt 1 tablespoon butter in a medium saucepan
over medium-high heat. Add shallots; cook,
stirring often, until slightly softened and light
golden, about 5 minutes. Transfer shallots
to bowl with greens. Add cream, milk, garlic,
and thyme sprigs to same saucepan; bring
to a simmer. Cook until mixture is thickened
and reduced to 1 1/2 cups, 10-12 minutes.
Discard thyme sprigs and garlic; stir in nutmeg.
Season mixture with salt and pepper.

Pour cream mixture over greens in bowl
and toss to evenly coat in sauce; season to
taste with salt and pepper. Transfer greens
mixture to prepared baking dish; sprinkle
Gruyère over. Top with breadcrumbs. Cover
dish with foil. DO AHEAD: Gratin can be
assembled 1 day ahead.

Tags:

Recent Review

Wonderful, but a ton of work to prep the greens. (To get them dry, I used the salad spinner and then squeezed them in a towel.) I agree with other reviewers that the breadcrumbs are a bit much - and I love breadcrumbs! The greens are so lovely, and the breadcrumbs bury them a bit. Would halve the crumbs next time. The inclusion of mustard greens is particularly inspired.